Poly(m-phenylene isophthalamide) is synthesized by the reaction of isophthaloyl chloride and m-phenylene diamine in dimethylacetamide (DMAc). Hydrogen chloride, a byproduct of the reaction, is corrosive and has an adverse effect on the polymer. The hydrogen chloride can be removed by contacting the solution with an ion-exchange resin in base form resulting in an HCl-free solution generally suitable for spinning. The present invention deals with regeneration of the spent or exhausted ion exchange resin.